Total error budget

The along-track power spectra of the different error components have been computed to check the consistency with the baseline requirements. These spectra, averaged across-track between 10~km and 60~km off nadir, are represented in Fig. 18. The total error budget with a 1-beam radiometer (thick black curve) is indeed slightly below the error requirement (thick red curve).

Note that the along-track power spectrum of the KaRIN noise (dark pink thick curve) sampled on a 2~km by 2~km grid is about 6 \(cm**2/(km/cy)\), which exceeds the requirements for a short wavelength. However, these requirements have been defined for wavelength exceeding 15~km in the plan (2 dimensions). Sampled at the Niquist frequency in the across swath direction (7.5~km), the noise drops down to 2 \(cm2/(km/cy)\) (thick dark pink curve).

FIG. 18: Error budget in the spectral domain, computed from a random realization of the simulator. The spectral densities have been averaged across-swath between 10~km and 60~km off nadir, consistently with the definition of the requirements.